1. Field of the Invention
The invention relates to a reconfigurable apparatus and method and, more particularly, to a reconfigurable apparatus and method for inspection of parts during a manufacturing process.
2. Description of the Invention Background
Manufacturers of mass-produced parts and products, such as vehicles, rely on automated inspection machines for quality control and rejection of defective parts. Consumer demand as well as considerations of safety and efficiency have led to the development of inspection systems that rely on machine vision coordinated with robotics and computer aided design to achieve precision and quality.
One such inspection system is the coordinate measurement machine or CMM disclosed in U.S. Pat. No. 5,402,582. The CMM uses three linear scales to measure the coordinates of an object in three-dimensional space. The measurements are made by a multi-jointed mechanical measuring arm, which includes measurement transducers. The CMM is connected to a controller in communication with a computer system that provides output for an operator. CMMs are used to measure a variety of different parts mainly in a metrology lab.
Because of the relatively high costs of CMMs, less accurate and less expensive conventional industrial robots equipped with contact sensors are often used for inspection of parts. Another, more accurate, robot-based system equipped with a non-contact sensor is disclosed in U.S. Pat. No. 6,166,811. This patent discloses a vision system adapted to retrieve data from the non-contact sensor and position data from a position reporting device and synchronize the image data from the sensor with the position data.
CMMs and robot-based systems operate by moving the sensor around the part to take measurements while the part is stationary. The inspection process is done off-line, preferably in an inspection room. It may take several hours to complete the inspection of a complicated automobile engine part. During this inspection time, bad or defective parts may be produced on the assembly line.
There remains, therefore, a need for an improved inspection system that can be used to inspect a family of parts during the manufacturing process, either on or adjacent to the production line and that overcomes the limitations, shortcomings and disadvantages of other known inspection systems.
The present invention meets the identified needs, as well as other needs, as will be more fully understood following a review of this specification and drawings.
One embodiment of the invention includes an inspection apparatus that comprises a conveyor line for moving a first part during a manufacturing process. The conveyor line is either a part of or adjacent to the moving production line. The inspection apparatus also includes a plurality of non-contact sensors, which are mounted on stationary supports around the conveyor line. One or more of the plurality of sensors may be enclosed within an environmentally-controlled chamber. The sensors measure a characteristic of the first part, such as, for example, parallelism, flatness, profile, etc., and produce inspection outputs. The sensors can be reconfigured for inspection of at least one different characteristic of a second part. The second part may be, for example, a new or redesigned part of the same or a related family. The same part in different orientation with respect to the inspection machine or at a different location along the production line and at a different stage during the manufacturing process may also be re-inspected. The apparatus may include shock absorption or vibration isolators. The apparatus may also include a computer system that receives the sensor inspection outputs and produces operator-accessible information. The apparatus may further include an entrance tag reader and an exit tag reader to read and write information from a tag attached to a fixture that holds the inspected part.
An additional embodiment of the invention also includes a system for inspecting a first part and a second part. The system comprises a conveyor line, a plurality of stationary supports in proximity to the conveyor line and a plurality of non-contact sensors, which are mounted on stationary supports around the conveyor line. The sensors can be reconfigured for inspection of at least one different characteristic of the second part. The same part in a different orientation with respect to the inspection machine or at a different location along the production line and at a different stage during the manufacturing process may also be re-inspected. The apparatus may also include a computer system that has a communication module in communication with the sensors and the conveyor line, and a decision module that compares the inspection outputs for each inspected part with a computer-stored design of the part within predetermined tolerances. The computer system further includes a control module that issues a command when a tolerance is exceeded. The computer system may further include a feedback module in communication with a Numerical Controller (NC) for the manufacture of the inspected part. The command may optionally be sent to a conveyor controller to stop the conveyor line. A command may also optionally be sent to the numerical controller to stop the numerical controller or to modify a predetermined path of the numerical controller.
Another embodiment of the invention, and more particularly of the inspection system, includes a conveyor line, a plurality of stationary supports near the conveyor line and a machine vision system comprising a plurality of non-contact sensors, at least one camera and a machine vision processor that communicates with the sensors and the camera and issues a command to a Programmable Logic Controller (PLC) regarding the production of a first part. The sensors and the camera are reconfigurably mounted on any of the supports such that the inspection system can be quickly reconfigured for inspecting a second part, such as a new or redesigned part of the same or related family of parts or to re-inspect the same part at a different stage of the manufacturing process.
In an alternate embodiment, the inspected part may be stationary and the supports on which the sensors are reconfigurably mounted may be moving in relation to the stationary part.
Another embodiment of the invention includes a method for inspecting parts during a manufacturing process. The method comprises mounting a plurality of non-contact electro-optical sensors in proximity to a moving line holding a first part, measuring at least one characteristic of the first part, producing an inspection output and converting the inspection output to operator-accessible information. The method also includes reconfiguring the sensors for inspection of a second part with different characteristics. The method may further include mounting a camera that interfaces with the sensors and is directed to the conveyor line, and reconfiguring the camera for inspecting the second part.
Yet another embodiment of the invention includes a method for inspecting and re-inspecting a part during a manufacturing process. The method comprises mounting a plurality of non-contact electro-optical sensors in proximity to a moving line holding the part, measuring at least one characteristic of the part at a first stage of the manufacturing process, producing an inspection output and converting the inspection output to operator-accessible information. The method also includes reconfiguring the sensors for inspection of the part at a second stage of the manufacturing process.
It is a feature of at least one embodiment of the invention to provide an inspection system that can be used to inspect a part as the part moves on a production line or adjacent to a production line.
Another feature of at least one embodiment of the invention is to provide an inspection system that is easily and quickly reconfigurable for inspection of a different, new or redesigned, part of the same or related family of parts, and for re-inspection of the same part at different stages of the manufacturing process, including at a different location with respect to the production line or at different orientation with respect to the inspection machine.
It is a feature of yet another embodiment of the invention to provide fast feedback for the correction or modification of the manufacturing process so that the production of defective or nonconforming parts is minimized.
It is another feature of various embodiments of the invention to provide an inspection applicable to a medium or high-volume production of a family of parts where switchovers among the parts within the family may be the practice.
Accordingly, various embodiments of the invention provide solutions to the limitations, shortcomings and disadvantages of other inspection systems and methods. Those of ordinary skill in the art will readily appreciate, however, that these and other details, features and advantages will become further apparent as the following detailed description proceeds.